52 auld: methods of gas warfare 



1 part in 1000, whereas concentrations of two or three per cent 

 can be met by respirators depending on chemical reactivity. 

 One such respirator is a box of chemicals connected by a flexible 

 tube with a face-piece fitting around the contours of the face, 

 and provided with a mouthpiece and nosepiece. 



As regards the chemicals used there is no secret, for the Ger- 

 mans have many of the same things. Active absorbent char- 

 coal is one of the main reliances, and is another suggestion that 

 we owe to the Russians. Wood charcoal was used in one of 

 their devices and was effective, but most of the Russian soldiers 

 had no protection at all. 



We wanted to protect against chlorine, acids and acid-forming 

 gases, phosgene, etc., arid at one time were fearful of meeting 

 large quantities of hydrocyanic (prussic) acid (HCN). At one 

 period every prisoner taken talked about the use of prussic acid, 

 saying that the Kaiser had decided to end the war and had 

 given permission to use prussic acid. Protection was evidently 

 needed against it. The three things that then seemed most 

 important were: (1) chlorine and phosgene; (2) prussic acid; 

 (3) lachrymators. Charcoal and alkaline permanganate will 

 protect against nearly everything used, even up to concen- 

 trations of ten per cent for short periods. 



The German apparatus, developed about the same time, is of 

 different pattern, and is still employed. It consists of a small 

 drum, attached directly to the front of the face-piece, and 

 weighs less than the British respirator but must be changed 

 more frequently. It has no mouthpiece. The chemicals are 

 in three layers: first an inside layer of pumice with hexameth- 

 ylenetetramine, in the middle a layer of charcoal (sometimes 

 blood charcoal), and outside baked earth soaked in potassium 

 carbonate solution and coated with fine powdered charcoal. 



As regards the future of the gas cloud, it may be looked upon 

 as almost finished. There are so many conditions that have to 

 be fulfilled in connection with it that its use is limited. It is 

 very unlikely that the enemy will be able to spring another 

 complete surprise with a gas cloud. 



The case is different with gas shells. The gas shells are the 

 most important of all methods of using gas on the Western 



